<?php
/*
UPDATES
		2008-08-10  Fixed CSS comment stripping regex to add PCRE_DOTALL (changed from '/\/\*.*\*\//U' to '/\/\*.*\*\//sU')
		2008-08-18  Added lines instructing DOMDocument to attempt to normalize HTML before processing
		2008-10-20  Fixed bug with bad variable name... Thanks Thomas!
		2008-03-02  Added licensing terms under the MIT License
								Only remove unprocessable HTML tags if they exist in the array
		2009-06-03  Normalize existing CSS (style) attributes in the HTML before we process the CSS.
								Made it so that the display:none stripper doesn't require a trailing semi-colon.
		2009-08-13  Added support for subset class values (e.g. "p.class1.class2").
								Added better protection for bad css attributes.
								Fixed support for HTML entities.
		2009-08-17  Fixed CSS selector processing so that selectors are processed by precedence/specificity, and not just in order.
		2009-10-29  Fixed so that selectors appearing later in the CSS will have precedence over identical selectors appearing earlier.
		2009-11-04  Explicitly declared static functions static to get rid of E_STRICT notices.
		2010-05-18  Fixed bug where full url filenames with protocols wouldn't get split improperly when we explode on ':'... Thanks Mark!
								Added two new attribute selectors
		2010-06-16  Added static caching for less processing overhead in situations where multiple emogrification takes place
		2010-07-26  Fixed bug where '0' values were getting discarded because of php's empty() function... Thanks Scott!
		2010-09-03  Added checks to invisible node removal to ensure that we don't try to remove non-existent child nodes of parents that have already been deleted


*/
class Emogrifier {

		private $html = '';
		private $css = '';
		private $unprocessableHTMLTags = array('wbr');

		public function __construct($html = '', $css = '') {
			$this->html = $html;
			$this->css  = $css;
		}

		public function setHTML($html = '') { $this->html = $html; }
		public function setCSS($css = '') { $this->css = $css; }

	// there are some HTML tags that DOMDocument cannot process, and will throw an error if it encounters them.
	// these functions allow you to add/remove them if necessary.
	// it only strips them from the code (does not remove actual nodes).
		public function addUnprocessableHTMLTag($tag) { $this->unprocessableHTMLTags[] = $tag; }
		public function removeUnprocessableHTMLTag($tag) {
			if (($key = array_search($tag,$this->unprocessableHTMLTags)) !== false)
					unset($this->unprocessableHTMLTags[$key]);
		}

		// applies the CSS you submit to the html you submit. places the css inline
	public function emogrify() {
		$body = $this->html;
		// process the CSS here, turning the CSS style blocks into inline css
		if (count($this->unprocessableHTMLTags)) {
			$unprocessableHTMLTags = implode('|',$this->unprocessableHTMLTags);
			$body = preg_replace("/<($unprocessableHTMLTags)[^>]*>/i",'',$body);
		}

		//$encoding = mb_detect_encoding($body);
		$encoding = 'UTF-8';
		$body = mb_convert_encoding($body, 'HTML-ENTITIES', $encoding);

		$xmldoc =@ new DOMDocument;
		if(!is_object($xmldoc) || !method_exists($xmldoc,'loadHTML')) return $this->html;

		$xmldoc->encoding = $encoding;
		$xmldoc->strictErrorChecking = false;
		$xmldoc->formatOutput = true;
		//ACYBA MODIFICATION : let's avoid some warnings
		@$xmldoc->loadHTML($body);
		$xmldoc->normalizeDocument();

		$xpath = new DOMXPath($xmldoc);

		// before be begin processing the CSS file, parse the document and normalize all existing CSS attributes (changes 'DISPLAY: none' to 'display: none');
		// we wouldn't have to do this if DOMXPath supported XPath 2.0.
		$nodes = @$xpath->query('//'.'*[@style]');
		if ($nodes->length > 0) foreach ($nodes as $node) $node->setAttribute('style',preg_replace('/[A-z\-]+(?=\:)/Se',"strtolower('\\0')",$node->getAttribute('style')));

		// get rid of css comment code
		$re_commentCSS = '/\/\*.*\*\//sU';
		$css = preg_replace($re_commentCSS,'',$this->css);

		static $csscache = array();
		$csskey = md5($css);
		if (!isset($csscache[$csskey])) {

			// process the CSS file for selectors and definitions
			$re_CSS = '/^\s*([^{]+){([^}]+)}/mis';
			preg_match_all($re_CSS,$css,$matches);

			$all_selectors = array();
			foreach ($matches[1] as $key => $selectorString) {
				// if there is a blank definition, skip
				if (!strlen(trim($matches[2][$key]))) continue;

				// else split by commas and duplicate attributes so we can sort by selector precedence
				$selectors = explode(',',$selectorString);
				foreach ($selectors as $selector) {
					// don't process pseudo-classes
					if (strpos($selector,':') !== false) continue;
					$all_selectors[] = array('selector' => $selector,
						 'attributes' => $matches[2][$key],
						 'index' => $key, // keep track of where it appears in the file, since order is important
					);
				}
			}

		// now sort the selectors by precedence
		usort($all_selectors, array('self','sortBySelectorPrecedence'));

		$csscache[$csskey] = $all_selectors;
		}

		for($a = count($csscache[$csskey]) -1;$a>=0;$a--) {

			// query the body for the xpath selector
			$nodes = @$xpath->query($this->translateCSStoXpath(trim($csscache[$csskey][$a]['selector'])));
			if(empty($nodes)) continue;

			foreach($nodes as $node) {
				// if it has a style attribute, get it, process it, and append (overwrite) new stuff
				if ($node->hasAttribute('style')) {
					// break it up into an associative array
					$oldStyleArr = $this->cssStyleDefinitionToArray($node->getAttribute('style'));
					$newStyleArr = $this->cssStyleDefinitionToArray($csscache[$csskey][$a]['attributes']);

					// new styles overwrite the old styles (not technically accurate, but close enough)
					//Changed by Acyba, we don't overwrite the old styles, we keep them and add only the new ones
					//$combinedArr = array_merge($oldStyleArr,$newStyleArr);
					$combinedArr = array_merge($newStyleArr,$oldStyleArr);
					$style = '';
					foreach ($combinedArr as $k => $v) $style .= (strtolower($k) . ':' . $v . ';');
				} else {
					// otherwise create a new style
					$style = trim($csscache[$csskey][$a]['attributes']);
				}
				$node->setAttribute('style',$style);
			}
		}

		// This removes styles from your email that contain display:none. You could comment these out if you want.
		$nodes = $xpath->query('//'.'*[contains(translate(@style," ",""),"display:none")]');
		// the checks on parentNode and is_callable below are there to ensure that if we've deleted the parent node,
		// we don't try to call removeChild on a nonexistent child node
		if ($nodes->length > 0) foreach ($nodes as $node) if ($node->parentNode && is_callable(array($node->parentNode,'removeChild'))) $node->parentNode->removeChild($node);

		return $this->fixCompatibility($xmldoc->saveHTML());

	}

	private static function sortBySelectorPrecedence($a, $b) {
		$precedenceA = self::getCSSSelectorPrecedence($a['selector']);
		$precedenceB = self::getCSSSelectorPrecedence($b['selector']);

		// we want these sorted ascendingly so selectors with lesser precedence get processed first and
		// selectors with greater precedence get sorted last
		return ($precedenceA == $precedenceB) ? ($a['index'] < $b['index'] ? -1 : 1) : ($precedenceA < $precedenceB ? -1 : 1);
	}

	private static function getCSSSelectorPrecedence($selector) {
		static $selectorcache = array();
		$selectorkey = md5($selector);
		if (!isset($selectorcache[$selectorkey])) {
			$precedence = 0;
			$value = 100;
			$search = array('\#','\.',''); // ids: worth 100, classes: worth 10, elements: worth 1

			foreach ($search as $s) {
				if (trim($selector == '')) break;
				$num = 0;
				$selector = preg_replace('/'.$s.'\w+/','',$selector,-1,$num);
				$precedence += ($value * $num);
				$value /= 10;
			}
			$selectorcache[$selectorkey] = $precedence;
		}

		return $selectorcache[$selectorkey];
	}

	// right now we support all CSS 1 selectors and /some/ CSS2/3 selectors.
	// http://plasmasturm.org/log/444/
	private function translateCSStoXpath($css_selector) {

		$css_selector = trim($css_selector);
		static $xpathcache = array();
		$xpathkey = md5($css_selector);
		if (!isset($xpathcache[$xpathkey])) {
			// returns an Xpath selector
			$search = array(
				 '/\s+>\s+/', // Matches any F element that is a child of an element E.
				 '/(\w+)\s+\+\s+(\w+)/', // Matches any F element that is a child of an element E.
				 '/\s+/', // Matches any F element that is a descendant of an E element.
				 '/(\w)\[(\w+)\]/', // Matches element with attribute
				 '/(\w)\[(\w+)\=[\'"]?(\w+)[\'"]?\]/', // Matches element with EXACT attribute
				 '/(\w+)?\#([\w\-]+)/e', // Matches id attributes
				 '/(\w+|\*)?((\.[\w\-]+)+)/e', // Matches class attributes
			);
			$replace = array(
				 '/',
				 '\\1/following-sibling::*[1]/self::\\2',
				 '//',
				 '\\1[@\\2]',
				 '\\1[@\\2="\\3"]',
				 "(strlen('\\1') ? '\\1' : '*').'[@id=\"\\2\"]'",
				 "(strlen('\\1') ? '\\1' : '*').'[contains(concat(\" \",@class,\" \"),concat(\" \",\"'.implode('\",\" \"))][contains(concat(\" \",@class,\" \"),concat(\" \",\"',explode('.',substr('\\2',1))).'\",\" \"))]'",
			);
			$xpathcache[$xpathkey] = '//'.preg_replace($search,$replace,$css_selector);
		}
		return $xpathcache[$xpathkey];
	}

	private function cssStyleDefinitionToArray($style) {
		$definitions = explode(';',$style);
		$retArr = array();
		foreach ($definitions as $def) {
			if (empty($def) || strpos($def, ':') === false) continue;
			list($key,$value) = explode(':',$def,2);
			if (empty($key) || strlen(trim($value)) === 0) continue;
			$retArr[trim($key)] = trim($value);
		}
		return $retArr;
	}

	private function fixCompatibility($text){
		$replace = array();
		$replace['#<br>#Ui'] = '<br />';
		$replace['#<img([^>]*[^/])>#Ui'] = '<img$1 />';
		//We replace the header properly as it may display a non valid DOCTYPE...
		$replace['#<\!DOCTYPE[^>]*>#Usi'] = '<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">';
		$body = preg_replace(array_keys($replace),$replace,$text);

		//Just in case of...
		if(empty($body)) $body = $text;
		//Be careful with that line!
		//$body = mb_convert_encoding($body, 'UTF-8', 'HTML-ENTITIES');

		//Debug informations...
		//echo '<textarea cols="100" rows="10">'.htmlentities($text).'</textarea>';
		//echo '<textarea cols="100" rows="10">'.htmlentities($body).'</textarea>';
		return $body;

	}
}